This invention relates to the shipment of bulk materials in shipping vehicles and more particularly to a flexible liner suitable for installation in a standard international container or cargo vessel such as a trailer, truck, rail car or air or seagoing cargo storage space together with a method of installing the flexible insert within a generally rectangular container or cargo storage space. The term container" will be used hereinafter to cover containers, cargo vessels and cargo storage space. The term "bulk material" includes, but is not limited to substances in the form of powder, pellets, flakes or granules, and also includes liquids. Examples of bulk material include coffee beans, salt, grains and the like.
A large proportion of goods and bulk materials transported today are stored in rigid containers for movement. Many of these containers are of a standard size so that they may be used on both land based vehicles, ships and barges and may also be stacked aboard large seagoing vessels or aircraft. For economic reasons, it has been found desirable to ship bulk materials in containers and in order to do this, a flexible liner has been used in a standard container.
Prior to this invention, flexible containers have been used within standard containers of generally rectangular configuration. However, these containers are susceptible of opening and permitting the load to be lost by spillage when the door to the standard container at one end thereof is opened. There have been cases where laborers working with these containers have been injured during the unloading of the loads stored in these inserts for the standard containers. When cargo is loaded into a flexible insert or when the door of a container provided with a flexible insert is opened for inspecting the cargo, the flexible insert bulges outward, making it difficult and even impossible to reclose the door of the container.
Care must be taken to insure that the insert within the standard container is not applied in such a manner that it is movable within the container, because relative movement between the insert and the container may tear the wall of the flexible insert and cause the contents to spill. Unless steps are taken to secure the insert to the container and to provide means to maintain the rear end wall of the insert in close relation to the corresponding rear end wall of the container, problems arise. Spillage of material from a torn flexible insert may contaminate the container and make its further use impossible without first requiring very careful cleaning and scrubbing of the container to remove all vestiges of the contents of a previous load. Also, the flexible insert must resist tearing in cases where direct contact of the bulk material with the container would cause the container to contaminate the bulk material, or vice versa. Also, the flexible insert must be composed of a material that is impervious to the cargo with which the insert is loaded.
Many attempts have been made in the prior art to develop a technique of using flexible inserts for standard size containers as will be discussed in a review of patents that came to the attention of applicant's associates in the course of a novelty search and patent office prosecution.
U.S. Pat. No. 2,912,137 to Taylor, issued Nov. 10, 1959, discloses a reusable insert or liner for a container having a floor and four upstanding side walls forming a unitary structure and having a plurality of L-shaped flexible reinforcing elements spaced around the periphery of the structure.
U.S. Pat. No. 3,402,845 to Eriksson, issued Sep. 24, 1968, discloses collapsible containers of skeleton construction that contain diagonal stays near certain corners of the container. Each stay contains a turnbuckle to facilitate its dismantling or assembly as a rigid connection between adjacent horizontal frame members so that when the stays are rigid, the container opens to receive a load and when the stays are dismantled, the containers collapse for stacking.
U.S. Pat. No. 3,696,952, issued Oct. 10, 1972, and U.S. Pat. No. 3,868,042, issued Feb. 25, 1975, to Bodenheimer, disclose a flexible bag member adhered at spots to an empty container wall which has bulkheads wedged between the container sidewall that move with the insertion of a load of bulk material. The bulkhead is provided with suitable openings that are normally sealed during transport to facilitate loading and unloading of the liner within the container.
U.S. Pat. No. 3,951,284 to Fell, et al, issued Apr. 20, 1976, uses a stretchable connector means to support a flexible liner within the adjacent walls of a standard container.
U.S. Pat. No. 3,980,196 to Paulyson et al., issued Sep. 14, 1976, discloses a pair of flexible, load distributing, front cross members, a rear frame, and a rear bulkhead mounted on the rear frame to mount and securely retain a flexible bag as a liner within a freight container and support the bag against damage or rupture.
U.S. Pat. No. 4,054,226 to Bjelland, et al, issued Oct. 18, 1977, shows a flexible insert for use within a container. The flexible insert has structural front and rear frames, the front frame retaining the front end of a liner bag in generally rectangular configuration to transmit stresses on the bag to structural members of the container and a laterally curved rear bulkhead supporting the rear end of the bag relative to the standard container to prevent its rupture or collapse during loading or unloading of the flexible insert.
U.S. Pat. No. 4,232,803 to Muller, et al, issued Nov. 11, 1980, shows a system that utilizes a pair of retainers to support a flexible liner within a container. This system requires a two door opening.
U.S. Pat. No. 4,601,405 to Riemer, issued Jul. 22, 1986, discloses a device for closing an open end of a cargo holding sleeve used within a standard container. The device consists of three triangular sheets which are respectively connected at a base edge to separate side walls of the sleeve and the apex portions of the sheets are connected together to cooperate to close the end of the sleeve.
U.S. Pat. No. 4,792,239 to Hamada, et al, issued Dec. 20, 1988, discloses an adjustable belt for hanging a flexible inner bag to the inner wall of a container.
U.S. Pat. No. 4,863,339 to Krein, issued Sep. 5, 1989, discloses applying a vacuum between the outer wall of a flexible bag and the inner wall of a container within which the flexible bag is stored for shipment in order to facilitate removing the air between the flexible bag and the container.
European Patent publication 331,491 to Dorse, published Sep. 6, 1989, discloses a flexible insert bag reinforced by a harness for a snug fit within a container.
U.S. Pat. No. 4,875,596 to Lohse, issued Oct. 24, 1989, discloses a tubular flexible vessel supported within a container spaced from the container walls with its ends closed by a clamp connection.
U.S. Pat. No. 4,911,317 to Schloesser et al., issued Mar. 27, 1990, discloses a bag made of a flexible gas and water impermeable material placed within a 150 type shipping container. The bag has an entry flap positioned adjacent to the door of the container with an air and water resistant zipper sealing the flap with the bag, and having a resealable port for inflating and evacuating the bag to control its interior environment.
U.S. Pat. No. 5,040,693 to Podd et al., issued Aug. 20, 1991, discloses a liner for a cargo container that comprises an inflatable body and side connecting straps that are connected to the sides of the inner body and are releasably clamped to the side edge portions of the container floor, using elongated wooden slats over the connecting strips that are nailed to the container floor through the connecting strips.
U.S. Pat. No. 5,059,084 to Krein, issued Oct. 22, 1991, discloses a flexible liner inserted within a polygonal container to form an interior cavity between the outer surface of the liner and the inner surface of the container. A vacuum applied to the interior cavity shapes the liner to conform to the shape of the container.
A more recent novelty search reported the following publications as relevant to the presently claimed invention:
______________________________________ France - 2,461,661 Kleber-Colombes June 2, 1981 European - 0,274,417 Kaisha July 13, 1988 European - 0,280,493 Kaisha Aug. 31, 1988 European - 0,280,495 Kaisha Aug. 31, 1988 International - Chick Dec. 15, 1988 WO 88/09755 United Kingdom - Kaisha June 27, 1990 GB 2,226,300 United States - Hawkins Oct. 30, 1990 4,966,310 ______________________________________
None of the aforesaid publications incorporate internal obliquely extending reinforcing straps that are constructed and arranged for connection at one end to a rear door portion of an insert at their rear ends and to another portion of the insert to reinforce the rear door portion against outward bulging when the rear door of a container loaded with cargo within said flexible insert is opened.